Rehfeld et. al, U.S. Pat. No. 5,368,917, assigned to Saint Gobain Vitrage International, discloses an acoustic glazing for a vehicle, especially a motor vehicle. These articles serve to damp noises of aerodynamic origin (Col. 1, lines 49-51) at frequencies of more than 800 Hz. The '917 patent describes windshields having two glass sheets separated by a plastic sheet or air space interlayer.
Additional glass laminate constructions useful for noise insulation are disclosed in JP07081982, JP06191905, and JP06166551. Other laminates are disclosed in U.S. Pat. Nos. 4,427,734 and 5,154,953 and JP 06206739 and JP 05310450.
Conventional safety glass is discussed in the MCGRAW-HILL ENCYCLOPEDIA OF SCIENCE AND TECHNOLOGY, Vol. 16, pages 3 to 4 (1986). It is defined as a unitary structure formed of two or more sheets of glass between each of which is interposed a sheet of plastic, usually polyvinyl butyral. According to the reference it is typically produced by first assembling two clean and dry sheets of plate glass and a sheet of plastic under slight pressure to produce a void-free bond. The laminate is then pressed at 75-225 psi (0.5 to 1.5 megapascals) under heat at 239-302.degree. F. (115 to 150.degree. C.) long enough to unite. The reference indicates that for installation in surface vehicles the finished laminated glass is approximately 1/4 inch thick (6 mm) thick. For use in aircraft the finished glass laminate is thicker. The plastic interlayer has the ability to yield rather than rupture under impact. Due to this property and the adherence of the glass to the plastic, the laminated glass presents less hazard from flying or scattered glass chips in event of damage than would an equal thickness of glass. According to the reference, however, the nonrigid plastic layer lowers the modulus of rupture of the laminate to approximately 60 percent of that of monolithic glass at room temperature. The thermoplastic interlayer also makes other properties of safety glass appreciably temperature dependent. Optionally, safety glass has substantially the properties of the glass sheets of which it is made. However, according to the reference, above about 160.degree. F. (70.degree. C.) the organic plastic may deteriorate. Most safety glass is used in automotive vehicles where the plastic interlayer is 0.030 inch (0.75 mm) thick. According to the reference it is also used in ships, locomotives, railroad cars, aircraft, safety goggles and viewing windows. Formed from tempered glass and in multiple layers and built up to greater thickness, the laminate is used in bullet resisting structures in banks, jewelry display cases, vehicles, and test-chamber windows. The glass or plastic may be tinted to provide color filtering.
Safety glass is discussed also in "Questions & Answers, Answers To The Most Asked Questions About Residential Glass: Its Applications, Features and Benefits", Safeflex Home Page Oct. 25, 1996, pages 1-7,.http://www.monsanto.com//saflex/faq/.
A laminated pane is disclosed in U.S. Pat. No. 5,352,528, assigned to Saint-Gobain Vitrage International.